g. willikers wrote: When two batches of powder are mixed, how can you be sure that the mix is truly homogeneous.
What if the two batches are different and they don't mix entirely well?
What assurance is there that each and every cartridge will get exactly the same mix?
Just thinking out loud, here.

What makes you think that same line of questioning doesn't apply to the powder that we buy from the distributors? Our canister grade powders are blended to keep them within a tighter tolerance of performance than the bulk powders sold to the .mil and the ammo manufacturers. Why do you think that some batches of a particular powder exhibit a wider ES and SD than other batches of the same powder?